THORACIC CAVITY
LUNGS and
PLEURA
Pleura

Visceral pleura:
Covers and follows indentations of lung.

Parietal pleura:
Lines thoracic cavity.

Text: p 113, Fig. 1.23
Parietal Pleura Divisions
Costal pleura lines the ribs.
 Diaphragmatic pleura covers the
diaphragm.
 Mediastinal pleura lies against the
mediastinum.
 Cervical pleura extends above the level of
the first rib.
 Text: p 115, Fig. 1.24

Pleural Reflections

Costodiaphragmatic recess (space):
Space where costal and diaphragmatic
pleura meet.

Costomediastinal recess (space):
Space where mediastinal and costal pleura
meet.

Pulmonary ligament:
Transition between visceral and parietal
pleura at root of the lung.
Pleural Lines of Reflection

Cervical dome of pleura:
Level with neck of the first rib.
Anteriorly, 1.5-2.5 cm above the sternal end
of the clavicle.
Anterior margin extends obliquely behind the
sternoclavicular joint.
At sternal angle, the pleura is at the median
line and two sides stay in contact until the
fourth costal cartilage.
Text: p 115, Fig. 1.24A
Pleural Lines of Reflection

Right side:
 Leaves sternum at
7th costal cartilage.
 At 8th costal
cartilage at
midclavicular line.
 At 10th rib at
axillary line.
 At 11th rib at
scapular line.
 Extends to level of
body of T12 and
then ascends.
Pleural Lines of Reflection

Left side:
 Leaves sternum at
IC space 5.
 1.5 cm from sternal
margin at 6th costal
cartilage.
 Follows same
landmarks as right
side from this
point.
Right Lung Projections
Follows rib 1 to sternoclavicular joint.
 Located at median plane at sternal angle.
 Extends along median plane from 2nd
costal cartilage to 4th costal cartilage.
 Leaves sternum at 6th costal cartilage.
 At 6th rib at midclavicular line.

Right Lung Projections
At 8th rib at axillary line.
 At 10th rib at scapular line.
 Ends opposite T11.

Left Lung Projections

Same as right lung except:
Cardiac notch begins at 4th costal cartilage.
Horizontal at parasternal line.
Medial to costochondral junction at 6th
cartilage.
Right Lung Morphology

Oblique fissure :
Separates superior and inferior lobes.
Begins at base of scapular spine.
At 5-6th rib at midaxillary line.
Ends at 6th costochondral junction.

Text: p 122: Fig. 1.27
Right Lung Morphology

Horizontal fissure :
Separates superior and middle lobes.
Begins at axillary line.
Follows rib 4.
Left Lung Morphology

Oblique fissure:
Same as for right lung.

No horizontal fissure.
Lobes of the Lungs

Lobes
3 on right
2 on left
Supplied by secondary bronchi
Lobes of the Lungs

Lobules (bronchopulmonary segments)
10 on right
8 on left
Supplied by tertiary bronchi

Text: p 125 and 126, Fig. 1.28
Lobes of the Right Lung

Superior lobe:
Apical lobule
Posterior lobule
Anterior lobule

Middle lobe:
Lateral lobule
Medial lobule
Lobes of the Right Lung

Inferior lobe:
Superior lobule
Anterior basal lobule
Medial basal lobule
Lateral basal lobule
Posterior basal lobule
Lobes of the Left Lung

Superior lobe:
Apicoposterior lobule
Anterior lobule
Lingular lobule:
Homologous to middle lobe of right lung.
Superior lobule.
Inferior lobule.
Lobes of the Left Lung

Inferior lobe:
Superior lobule
Anterior basal lobule
Medial basal lobule
Lateral basal lobule
Posterior basal lobule
Bronchopulmonary Tree

Trachea
Supported by cartilaginous rings

Primary bronchi
Supported by cartilaginous rings

Secondary bronchi
Supported by cartilaginous rings

Tertiary bronchi
Bronchopulmonary Tree
Respiratory bronchi
 Alveolar sacs
 Alveoli

Trachea
Supported by “C”-shaped cartilage
segments.
 In superior mediastinum.
 Anterior to esophagus.
 Bifurcates into primary bronchi at sternal
angle.
 Carina.
 Text: p 125, Fig. 1.28

Right Primary Bronchus

Shorter, straighter, and larger than left:
Aspirated objects more commonly follow
right bronchus.

Gives off three secondary bronchi:
Superior to superior lobe of right lung.
Middle to middle lobe of right lung.
Inferior to inferior lobe of right lung.
Left Primary Bronchus
Twice as long as right primary bronchus.
 Gives off two secondary bronchi:

Superior to superior lobe of right lung.
Inferior to inferior lobe of right lung.

Angle between primary bronchi is 62
degrees.
Bronchopulmonary Tree

Secondary bronchi:
Supply lobes.

Tertiary bronchi:
Supply lobules (bronchopulmonary
segments)
Respiratory bronchi
 Alveolar sacs
 Alveoli

Lung Vascular Supply

One pulmonary artery to each lung:
Part of root of lung:
Lobar arteries:
One to each lobe
Segmental arteries:
To segments
Intrasegmental
Lung Vascular Supply

Two pulmonary veins from each lung:
Intersegmental

Text: p 129, Fig. 1.30
Bronchial Arteries
Supply bronchi
 Intrasegmental
 Supply tissues of lungs
 Two left bronchial arteries from thoracic
aorta
 Right bronchial artery origin is variable but
usually from first aortic intercostal artery.
 Text: p 127, Fig. 1.29

Bronchial Veins
Right to azygos vein.
 Left to accessory hemiazygos vein or left
superior intercostal veins.

Innervation of the Lungs

Anterior and posterior plexus:
Lie anterior and posterior to roots of lungs.
Contain parasympathetic fibers:
From vagus nerve (CN X).
Contain sympathetic fibers:
From T1-4.
Related to esophageal and aortic plexuses
posteriorly.
Text: p 133, Fig. 1.33